We actually removed the concept of a distributed cache from drill altogether. So currently nothing is replacing HazelCast.
The distributed cache was used for storing the initialization-data for intermediate fragments. Only leaf node fragments were sent via the RPC layer. But the distributed cache added a lot of complexity, and didn't provide very much benefit. We decided to get rid of it and simply send all PlanFragments via the rpc layer. On Mon, Mar 28, 2016 at 12:56 PM, Pradeeban Kathiravelu < [email protected]> wrote: > Thanks Neeraja for your quick response. > > May I know what replaced Hazelcast in that case? > > I mean, how does Drill distributed mode currently offer the multicast and > subnet scenarios, or are these scenarios not valid anymore? > > Regards, > Pradeeban. > > On Mon, Mar 28, 2016 at 3:52 PM, Neeraja Rentachintala < > [email protected]> wrote: > > > Its not currently used as far as I know. > > Drill used this at some point, but we removed it due to issues in > > multicast/subnet scenarios in Drill distributed mode. > > > > -Neeraja > > > > On Mon, Mar 28, 2016 at 12:49 PM, Pradeeban Kathiravelu < > > [email protected]> wrote: > > > > > Hi, > > > [1] states that Drill uses Hazelcast as an embedded distributed cache > to > > > distribute and store metadata and locality information. > > > > > > However, when I cloned the git repository and looked into the code, it > > does > > > not look like Hazelcast is used, except for some unused variable > > > definitions and pom definitions. > > > > > > I also found a resolved bug report on Hazelcast cluster membership [2]. > > > > > > May I know whether Hazelcast is currently used by Drill, and what does > > > exactly Drill achieve by using it? Relevant pointers to existing > > > discussions (if this was already discussed) or code location (if this > was > > > indeed implemented in Drill) are also appreciated. > > > > > > [1] > > > > > > > > > http://www.slideshare.net/Hadoop_Summit/understanding-the-value-and-architecture-of-apache-drill > > > [2] https://issues.apache.org/jira/browse/DRILL-489 > > > > > > Thank you. > > > Regards, > > > Pradeeban. > > > -- > > > Pradeeban Kathiravelu. > > > PhD Researcher, Erasmus Mundus Joint Doctorate in Distributed > Computing, > > > INESC-ID Lisboa / Instituto Superior Técnico, Universidade de Lisboa, > > > Portugal. > > > Biomedical Informatics Software Engineer, Emory University School of > > > Medicine. > > > > > > Blog: [Llovizna] http://kkpradeeban.blogspot.com/ > > > LinkedIn: www.linkedin.com/pub/kathiravelu-pradeeban/12/b6a/b03 > > > > > > > > > -- > Pradeeban Kathiravelu. > PhD Researcher, Erasmus Mundus Joint Doctorate in Distributed Computing, > INESC-ID Lisboa / Instituto Superior Técnico, Universidade de Lisboa, > Portugal. > Biomedical Informatics Software Engineer, Emory University School of > Medicine. > > Blog: [Llovizna] http://kkpradeeban.blogspot.com/ > LinkedIn: www.linkedin.com/pub/kathiravelu-pradeeban/12/b6a/b03 >
